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\bibitem{Ekstroem_etal1996} Ekstr{\"o}m, H., Kroug, M., Belitsky, V., Kollberg, E., Olsson, H., Goltsman, G., et al. (1996). Hot electron mixers for THz applications. In E. J. Rolfe, \& G. Pilbratt (Eds.), \textit{Proc. 30th ESLAB} (pp. 207--210).

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